Mineralogy
Mineral form (sulfide, oxide, native), microscopy and X-ray diffraction. Shows how the metal is associated with the matrix.
Every asset is assessed from its own material.
Tailings and low-grade deposits differ in mineralogy, chemistry, particle size and history. That is why the work starts with material characterization and proceeds in stages, with scope, assumptions and timing defined for each project.
Starting point
Tailings and low-grade ore call for different readings.
Tailings have already been crushed, milled and processed, and the source operation usually holds records of the chemistry used and the recovery achieved. These data guide characterization but do not replace it: variability across a dam or stockpile has to be measured.
For low-grade deposits, the assessment covers geology and mining as well as processing. Viability depends on the whole picture: material, scale, recovery, infrastructure, costs and commercial conditions.
In both cases, the goal is to understand how much metal is present, in what form, and which processing route makes sense for that material.
Characterization
Four readings of the material.
Chemistry
Elemental analysis and grade per element of interest, including contaminants that affect processing or marketing.
Particle size
Size distribution and liberation by fraction. Shows in which range the metal concentrates.
Process response
Bench tests and, where indicated, pilot-scale runs. They measure how this material behaves on the proposed route.
Sampling
A sampling plan for each asset.
Sample size, collection points and protocol are defined according to the size, heterogeneity and history of the asset. The plan aims to represent the material that would actually be processed.
- Collection at multiple points and depths, with splitting, homogenization and chain of custody.
- Bench tests to define reagents and configuration.
- Pilot run, when the project stage warrants it.
NoteFor operating assets, sampling may come from run-of-mine (ROM) material. For deposits not yet mined, it follows the exploration campaign and the metallurgical testwork planned for the project.
Stages
Stages of a project.
01
Preliminary screening — review of available information: location, material type, estimated volume, history and existing data. Determines whether to proceed and the scope of the next stage.
02
Characterization — sample preparation, mineralogy, chemistry, particle size and bench tests.
03
Pilot — pilot-scale processing to confirm process parameters, when the project stage warrants it.
04
Technical and economic evaluation — estimates of recovery, costs and capital, with stated assumptions and sensitivity analysis.
05
Structuring — agreeing the format with the asset owner: acquisition, joint venture, royalty or contract operation.
Timing and scope of each stage are defined at the start of the work, according to the asset and the information available.
Deliverables
What the assessment produces.
Material characterization
Mineralogical, chemical and particle-size data, with the methodology and laboratories used.
Test results
Recovery observed per element of interest, with the conditions under which it was measured.
Technical and economic evaluation
Cost and capital estimates, assumptions, sensitivities and stated limitations.
Next-step recommendation
Whether and how to proceed: further testwork, pilot, environmental studies or commercial structuring.
Next step
An assessment with assumptions and limitations, not an early certainty.
The result of each stage is a basis for decision for the asset owner and for Green Mining. A project's figures apply to that material under those conditions, and do not automatically transfer to other assets.